A new index of prognostic severity for chronic asthma

Primary Care Asthma Attack Prediction Models for Adults: A Systematic Review of Reported Methodologies and Outcomes

Prognostic models hold great potential for predicting asthma exacerbations, providing opportunities for early intervention, and are a popular area of current research. However, it is unclear how models should be compared and contrasted, given their differences in both design and performance, particularly with a view to potential implementation in routine practice. This systematic review aimed to identify novel predictive models of asthma attacks in adults and compare differences in construction related to populations, outcome definitions, prediction time horizons, algorithms, validation, and performance estimation. Twenty-five studies were identified for comparison, with varying definitions of asthma attacks and prediction event time horizons ranging from 15 days to 30 months. The most commonly used algorithm was logistic regression (20/25 studies); however, none of the six which tested multiple algorithms identified it as highest performing algorithm. The effect of various study design characteristics on performance was evaluated in order to provide context to the limitations of highly performing models. Models used a variety of constructs, which affected both their performance and their viability for implementation in routine practice. Consultation with stakeholders is necessary to identify priorities for model refinement and to create a benchmark of acceptable performance for implementation in clinical practice.

Blood eosinophils, fractional exhaled nitric oxide and the risk of asthma attacks in randomised controlled trials: protocol for a systemic review and control arm patient-level meta-analysis for clinical prediction modelling

INTRODUCTION

The reduction of the risk of asthma attacks is a major goal of guidelines. The fact that type-2 inflammatory biomarkers identify a higher risk, anti-inflammatory responsive phenotype is potentially relevant to this goal. We aim to quantify the relation between blood eosinophils, exhaled nitric oxide (FeNO) and the risk of severe asthma attacks.

METHODS AND ANALYSIS

A systematic review of randomised controlled trials (RCTs) will be conducted by searching MEDLINE from January 1993 to April 2021. We will include RCTs that investigated the effect of fixed treatment(s) regimen(s) on severe asthma exacerbation rates over at least 24 weeks and reported a baseline value for blood eosinophils and FeNO. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and the methodological appraisal of the studies will be assessed by the Cochrane Risk-of-Bias Tool for RCTs. Study authors will be contacted to request anonymised individual participant data (IPD) for patients randomised to the trial's control arm. An IPD meta-analysis will be performed for multivariable prognostic modelling with performance assessment (calibration plots and the c-statistic) in a cross-validation by study procedure. The outcome to predict is the absolute number of severe asthma attacks to occur in the following 12 months if anti-inflammatory therapy is not changed (ie, annualised number of attacks requiring ≥3 days of systemic corticosteroids and/or hospitalisation if the patient was randomised to the control arm of an RCT). A summary prognostic equation and risk stratification chart will be reported as a basis for further analyses of individualised treatment benefit.

ETHICS AND DISSEMINATION

The protocol has been reviewed by the relevant Oxford academic ethics committee and found to comprise fully anonymised data not requiring further ethical approbation. Results will be communicated in an international meeting and submitted to a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021245337.

Exacerbations in Adults with Asthma: A Systematic Review and External Validation of Prediction Models

BACKGROUND

Several prediction models assessing future risk of exacerbations in adult patients with asthma have been published. Applicability of these models is uncertain because their predictive performance has often not been assessed beyond the population in which they were derived.

OBJECTIVE

This study aimed to identify and critically appraise prediction models for asthma exacerbations and validate them in 2 clinically distinct populations.

METHODS

PubMed and EMBASE were searched to April 2017 for reports describing adult asthma populations in which multivariable models were constructed to predict exacerbations during any time frame. After critical appraisal, the models' predictive performances were assessed in a primary and a secondary care population for author-defined exacerbations and for American Thoracic Society/European Respiratory Society-defined severe exacerbations.

RESULTS

We found 12 reports from which 24 prediction models were evaluated. Three predictors (previous health care utilization, symptoms, and spirometry values) were retained in most models. Assessment was hampered by suboptimal methodology and reporting, and by differences in exacerbation outcomes. Discrimination (area under the receiver-operating characteristic curve [c-statistic]) of models for author-defined exacerbations was better in the primary care population (mean, 0.71) than in the secondary care population (mean, 0.60) and similar (0.65 and 0.62, respectively) for American Thoracic Society/European Respiratory Society-defined severe exacerbations. Model calibration was generally poor, but consistent between the 2 populations.

CONCLUSIONS

The preservation of 3 predictors in models derived from variable populations and the fairly consistent predictive properties of most models in 2 distinct validation populations suggest the feasibility of a generalizable model predicting severe exacerbations. Nevertheless, improvement of the models is warranted because predictive performances are below the desired level.

Intermittent versus daily inhaled corticosteroids for persistent asthma in children and adults

BACKGROUND

Daily inhaled corticosteroids (ICS) are the recommended mainstay of treatment in children and adults with persistent asthma. However, often, ICS are used intermittently by patients or recommended by physicians to be used only at the onset of exacerbations.

OBJECTIVES

The aim of this review was to compare the efficacy and safety of intermittent versus daily ICS in the management of children and adults with persistent asthma and preschool-aged children suspected of persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov web site up to October 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared intermittent ICS versus daily ICS in children and adults with persistent asthma. No co-interventions were permitted other than rescue relievers and oral corticosteroids used during exacerbations.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, methodological quality and extracted data. The primary efficacy outcome was the number of patients with one or more exacerbations requiring oral corticosteroids and the primary safety outcome was the number of patients with serious adverse health events. Secondary outcomes included exacerbations, lung function tests, asthma control, adverse effects, withdrawal rates and inflammatory markers. Equivalence was assumed if the risk ratio (RR) estimate and its 95% confidence interval (CI) were between 0.9 and 1.1. Quality of the evidence was assessed using GRADE.

MAIN RESULTS

Six trials (including one trial testing two relevant protocols) met the inclusion criteria for a total of seven group comparisons. The four paediatric trials (two involving preschool children and two school-aged children) and two adult parallel-group trials, lasting 12 to 52 weeks, were of high methodological quality. A total of 1211 patients with confirmed, or suspected, persistent asthma contributed to the meta-analyses. There was no statistically significant group difference in the risk of patients experiencing one or more exacerbations requiring oral corticosteroids (1204 patients; RR 1.07; 95% CI 0.87 to 1.32; the large confidence interval translates into a risk of exacerbations in the intermittent ICS group varying between 17% and 25%, assuming a 19% risk with daily ICS). Age, severity of airway obstruction, step-up protocol used during exacerbations and trial duration did not significantly influence the primary efficacy outcome. No group difference was observed in the risk of patients with serious adverse health events (1055 patients; RR 0.82; 95% CI 0.33 to 2.03). Compared to the daily ICS group, the intermittent ICS group displayed a smaller improvement in change from baseline peak expiratory flow rate (PEFR) by 2.56% (95% CI -4.49% to -0.63%), fewer symptom-free days (standardised mean difference (SMD) -0.15 (95% CI -0.28 to -0.03), fewer asthma control days -9% (95% CI -14% to -4%), more use of rescue β2-agonists by 0.12 puffs/day (95% CI 0 to 0.23) and a greater increase from baseline in exhaled nitric oxide of 16.80 parts per billion (95% CI 11.95 to 21.64). There was no significant group difference in forced expiratory volume in one second (FEV1), quality of life, airway hyper-reactivity, adverse effects, hospitalisations, emergency department visits or withdrawals. In paediatric trials, intermittent ICS (budesonide and beclomethasone) were associated with greater growth by 0.41 cm change from baseline (532 children; 95% CI 0.13 to 0.69) compared to daily treatment.

AUTHORS' CONCLUSIONS

In children and adults with persistent asthma and in preschool children suspected of persistent asthma, there was low quality evidence that intermittent and daily ICS strategies were similarly effective in the use of rescue oral corticosteroids and the rate of severe adverse health events. The strength of the evidence means that we cannot currently assume equivalence between the two options.. Daily ICS was superior to intermittent ICS in several indicators of lung function, airway inflammation, asthma control and reliever use. Both treatments appeared safe, but a modest growth suppression was associated with daily, compared to intermittent, inhaled budesonide and beclomethasone. Clinicians should carefully weigh the potential benefits and harm of each treatment option, taking into account the unknown long-term (> one year) impact of intermittent therapy on lung growth and lung function decline.

Intermittent versus daily inhaled corticosteroids for persistent asthma in children and adults

BACKGROUND

Daily inhaled corticosteroids (ICS) are the recommended mainstay of treatment in children and adults with persistent asthma. Yet often, ICS are used intermittently by patients or recommended by physicians to be used only at the onset of exacerbations.

OBJECTIVES

The aim of this review was to compare the efficacy and safety of intermittent versus daily ICS in the management of children and adults with persistent asthma and preschool-aged children suspected of persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov website up to December 2011.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared intermittent ICS versus daily ICS in children and adults with persistent asthma. No co-interventions were permitted other than rescue relievers and oral corticosteroids used during exacerbations.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, methodological quality and extracted data. The primary efficacy outcome was the number of patients with one or more exacerbations requiring oral corticosteroids and the primary safety outcome was the number of patients with serious adverse health events. Secondary outcomes included exacerbations, lung function tests, asthma control, adverse effects, withdrawal rates and inflammatory markers. Equivalence was assumed if the risk ratio (RR) estimate and its 95% confidence interval (CI) were between 0.9 and 1.1.

MAIN RESULTS

Six trials (including one trial testing two relevant protocols) met the inclusion criteria for a total of seven group comparisons. The four paediatric trials (two involving preschool children and two school-aged children) and two adult parallel-group trials, lasting 12 to 52 weeks, were of high methodological quality. A total of 1211 patients with confirmed, or suspected, persistent asthma contributed to the meta-analyses. There was no statistically significant group difference in the risk of patients experiencing one or more exacerbations requiring oral corticosteroids (1204 patients; RR 1.07; 95% CI 0.87 to 1.32). The patients' age, severity of airway obstruction, step-up protocol used during exacerbations and trial duration did not significantly influence the primary efficacy outcome. No group difference was observed in the risk of patients with serious adverse health events (1055 patients; RR 0.82; 95% CI 0.33 to 2.03). Compared to the daily ICS group, the intermittent ICS group displayed a smaller improvement in change from baseline peak expiratory flow rate (PEFR) by 2.56% (95% CI -4.49% to -0.63%), fewer symptom-free days (standardised mean difference (SMD) -0.15 (95% CI -0.28 to -0.03), fewer asthma control days -9% (95% CI -14% to -4%), more use of rescue β(2)-agonists by 0.12 puffs/day (95% CI 0 to 0.23) and a greater increase from baseline in exhaled nitric oxide of 16.80 parts per billion (95% CI 11.95 to 21.64). There was no significant group difference in forced expiratory volume in one second (FEV(1)), quality of life, airway hyper-reactivity, adverse effects, hospitalisations, emergency department visits or withdrawals. In paediatric trials, intermittent ICS (budesonide and beclomethasone) were associated with greater growth by 0.41 cm change from baseline (532 children; 95% CI 0.13 to 0.69) compared to daily treatment.

AUTHORS' CONCLUSIONS

In children and adults with persistent asthma and in preschool children suspected of persistent asthma, intermittent and daily ICS strategies did not significantly differ in the use of rescue oral corticosteroids and the rate of severe adverse health events, neither did they reach equivalence. Daily ICS was superior to intermittent ICS in several indicators of lung function, airway inflammation, asthma control and reliever use. Both treatments appeared safe, but a modest growth suppression was associated with daily, compared to intermittent, inhaled budesonide and beclomethasone. The clinician should carefully weigh the potential benefits and harm of each treatment option, taking into account the unknown long-term (> one year) impact of intermittent therapy on lung growth and lung function decline.

Predicting an asthma exacerbation in children 2 to 5 years of age

BACKGROUND

Asthma exacerbations in young children are prevalent. Identification of symptoms or other factors that are precursors of asthma exacerbations would be useful for early treatment and prevention.

OBJECTIVES

To determine whether diary symptoms and beta2-agonist use before an exacerbation could predict an asthma exacerbation in children 2 to 5 years of age.

METHODS

Post hoc analyses were conducted on data collected in a study of 689 patients 2 to 5 years of age with asthma symptoms, randomly assigned to montelukast, 4 mg, or placebo daily for 12 weeks. During the study, 196 patients had an exacerbation. Caregiver-reported information (daytime cough, breathing difficulties, limitation of activity, nighttime cough or awakening, daytime and nighttime beta2-agonist use) were analyzed using general estimating equations with an exchangeable within-subject log odds ratio regression structure to identify predictors of an exacerbation.

RESULTS

Average symptom scores and beta2-agonist use increased significantly before exacerbation but at different rates. A combination of daytime cough and wheeze and nighttime beta2-agonist use 1 day before the exacerbation was identified as strongly predictive of an exacerbation. These methods predicted 149 (66.8%) of the exacerbations with a very low false-positive rate of 14.2%.

CONCLUSIONS

No individual symptom was predictive of an imminent asthma exacerbation, but a combination of increased daytime cough, daytime wheeze, and nighttime beta2-agonist use 1 day before an asthma exacerbation was a strong predictor of an exacerbation in children.

Past, present and future--beta2-adrenoceptor agonists in asthma management

The beta-adrenoceptor agonists (beta-agonists) have been used to relieve bronchoconstriction for at least 5000 years. beta-agonists are based on adrenaline and early forms, such as isoprenaline, Lacked bronchial selectivity and had unpleasant side effects. Modern beta-agonists are more selective for the beta2-adrenoceptors (beta2-receptors) located in bronchial smooth muscle and have less cardiotoxicity. Traditional beta2-adrenoceptor agonists (beta2-agonists), such as salbutamol, terbutaline and fenoterol, were characterised by a rapid onset but relatively short duration of action. While valuable as reliever medication, their short duration gave inadequate night-time relief and limited protection from exercise-induced bronchoconstriction. beta2-agonists with longer durations of action, formoterol and salmeterol, were subsequently discovered or developed. When combined with inhaled corticosteroids they improved lung function, and reduced symptoms and exacerbations more than an increased dose of corticosteroids. However, tolerance to the bronchprotective effects of long-acting beta2-agonists and cross-tolerance to the bronchodilator effects of short-acting beta2-agonists is apparent despite use of inhaled corticosteroids. The role of beta2-receptor polymorphisms in the development of tolerance has yet to be fully determined. Formoterol is unique in having both a long-lasting bronchodilator effect (> 12 h) and a fast onset of action (1-3min from inhalation), making it effective both as maintenance and reliever medication. The recent change in classification from short- and long-acting beta2-agonists to rapid-acting and/or long-acting agents reflects the ongoing evolution of beta2-agonist therapy.

Diurnal variability of peak expiratory flow

Diurnal variation in peak expiratory flow (PEFvar) has been suggested as a surrogate for bronchial hyperreactivity, and may be a useful tool in the management of bronchial asthma. Several indices have been postulated to measure PEFvar; however, the number of daily measurements and the timing of recordings are not clearly established. Although several investigators have defined ranges for PEFvar in healthy individuals, clear cutoff values that differentiate asthmatics from others are not available. Despite this shortcoming, PEFvar is an important measurement in screening and diagnosis of asthma in population-based studies, as well as for assessing disease severity and prognosis. Treatment of asthma with either inhaled corticosteroids or bronchodilators may influence the magnitude of PEFvar in a complex fashion. Therefore, PEFvar should only be interpreted in conjunction with other clinical and laboratory information.

Effect of montelukast, a once-daily leukotriene receptor antagonist, on peak expiratory flow variability

BACKGROUND

Peak expiratory flow (PEF) is an important measure of airway functin in asthma. PEF variability (PEFvar) assessment is described in asthma treatment guidelines as another means of evaluating patient status and response to therapy.

OBJECTIVE

The goal of this study was to determine the clinical effect of oral montelukast, a leukotriene receptor antagonist, on PEFvar in asthmatic patients and to assess the relationship of PEFvar with other clinical measures.

METHODS

This was a retrospective analysis of data from a multicenter, randomized, double-blind, placebo-controlled, parallel-group study, details of which have been published previously. Eligible patients had chronic stable asthma, had a forced expiratory volume in 1 second (FEV1) that was 50% to 85% of the predicted value, used inhaled beta-agonists, had at least 15% improvement in absolute FEV1 after inhaled beta-agonist administration, and showed a minimal predefined level of daytime asthma symptoms. Treatment consisted of a 2-week, single-blind, placebo run-in period followed by a 12-week, double-blind treatment period (montelukast 10 mg or matching placebo once daily at bedtime).

RESULTS

Six hundred eighty-one patients (age range, 15-79 years) were randomized to treatment at 50 centers. Baseline PEFvar was 11.44% +/- 6.55% and 10.62% +/- 6.48% in the montelukast and placebo groups, respectively. PEFvar decreased 20.1% and 7.5% from baseline in the montelukast and placebo groups, respectively. The between-group difference was significant (P < 0.001). PEFvar had low correlation with other clinical measures.

CONCLUSIONS

Over 12 weeks of treatment, montelukast significantly reduced PEFvar compared with placebo, indicating improved asthma control. The relative reduction in PEFvar was similar in patients with different degrees of variability at baseline. PEFvar did not correlate highly with other outcome variables and may measure different aspects of the disease.

Assessment of a medication-based asthma index for population research

Asthma management guidelines recommend the use of preventive medications in sufficient amounts to control asthma symptoms. The validity of a medication use index as a proxy for asthma severity has not been established. We recruited 1,279 Ontario adults with asthma or parents of children with asthma from a community-based surveillance program in 1995-96. Participants completed a telephone questionnaire at baseline, 3 and 6 mo. The questionnaire gathered information about asthma medication use, health care utilization, and symptoms. Asthma was classified as mild in 28%, moderate in 49%, or severe in 23% of patients based on the amount and types of medication used. There were significant differences among groups in health resource use such that adults with higher medication use visited primary care physicians and specialists more frequently, had pulmonary functions tests more frequently, and were admitted to hospital more frequently. The findings among children were similar. There were weak positive correlations between medication use and symptom frequency in adults and children. We conclude that a medication use index may be useful in population-based research where clinical asthma severity data are lacking. Such an index is distinct from but is related to disease control.

Predicting emergency department utilization in adults with asthma: a cohort study

A consecutive sample of 378 adults with asthma were assessed at a university asthma program and then interviewed 1 year later regarding their need for emergency department (E.D.) asthma treatment. The purpose of this prospective cohort study was to determine whether any of their initial features could predict their subsequent need for E.D. asthma treatment. At one year, a total of 73 of the subjects had attended emergency departments for asthma. On entry, the 73 subjects had demonstrated more self-reported lifestyle restriction from asthma and more hospital admissions E.D. visits for asthma as well as poorer asthma control or than had the 305 subjects who had not required E.D. asthma treatment since entry to the cohort. This study suggests that special attention should be paid to subjects with asthma that interferes with their lifestyle and to those who have needed hospital admission for asthma.

Mild exacerbations and eosinophilic inflammation in patients with stable, well-controlled asthma after 1 year of follow-up

OBJECTIVES

To determine the time to exacerbation and probability of a mild exacerbation of asthma, and the impact of eosinophilic inflammation on these parameters in patients with stable, well-controlled asthma.

PATIENTS AND METHODS

A cohort of 31 patients with stable, well-controlled asthma receiving inhaled steroid treatment regularly were followed up for 1 year or until a mild exacerbation occurred. Mild exacerbation was defined as symptoms of asthma lasting > 48 h with a fall in peak expiratory flow > 20%. FEV(1), provocative concentration of methacholine causing a 20% fall in FEV(1), eosinophil count, and eosinophilic cationic protein (ECP) levels in blood and in sputum were measured at the first visit and every 2 months.

RESULTS

At baseline, the mean (SD) eosinophil count was 0.39 x 10(9)/L (0.21 x 10(9)/L) in blood and 13% (14%) in sputum; ECP was 30 microg/L (28 microg/L) in blood and 75 microg/L (85 microg/L) in sputum. Thirteen subjects experienced a mild exacerbation during the 1-year follow-up period. The mean time to mild exacerbation was 293 days (95% confidence interval [CI], 248 to 337 days), and the cumulative probability of not experiencing a mild exacerbation in 1 year was 49% (95% CI, 39 to 59%). An increased risk of mild exacerbation was associated with blood eosinophil count > 0.4 x 10(9)/L (relative risk 4.5; 95% CI of relative risk, 1.8 to 38.0), blood ECP > 20 microg/L (relative risk, 2.1; 95% CI of relative risk, 1.0 to 9.2), and sputum ECP > 40 microg/L (relative risk, 2.5; 95% CI of relative risk, 1.2 to 11.2), but was unassociated with other variables.

CONCLUSIONS

Patient with stable, well-controlled asthma are at risk of mild exacerbation during 1 year of follow-up despite regular inhaled steroid treatment. Eosinophilic inflammation expressed as eosinophil count and ECP is associated with higher risk of mild exacerbation.

A childhood asthma severity scale: symptoms, medications, and health care visits

BACKGROUND

Although there are current measures to evaluate childhood asthma severity for clinical diagnosis and treatment, there is no standard valid measure to evaluate childhood asthma severity for large-scale epidemiologic studies.

OBJECTIVES

To develop and test a childhood asthma severity scale (CHAS) for clinimetric validity and to determine differences in symptoms, medication use, and health care visits by participant characteristics.

METHODS

Eight hundred ninety-seven actively asthmatic children under the age of 12 years were selected from a general population of children. Children were selected from a screening questionnaire administered at six Connecticut hospitals that serve large minority populations in Bridgeport, New Haven, Hartford, and Danbury and one hospital serving south central Massachusetts. Twelve-month baseline data for a prospective cohort study of childhood asthma severity were collected on a monthly basis through home interviews. Home interviews addressed questions on daily symptoms, medication use, and health care visits. A severity scale was constructed using three dimensions: symptoms, medication use, and health care visits.

RESULTS

CHAS has sufficient preliminary content, construct, and predictive validity. Despite similarities in symptoms, there were health care utilization and medication differentials according to race and ethnicity, insurance status, family income, and maternal education.

CONCLUSIONS

CHAS is a potentially useful measure of asthma severity for large-scale epidemiologic studies. It seems that CHAS has sufficient clinimetric properties.

Early discharge of patients hospitalized with acute asthma: a controlled study

There is no consensus on the optimal length of stay and timing of release from hospital in patients admitted with acute asthma. We hypothesize that it might be safe to discharge patients from hospital once they have responded clinically to intensive anti-asthma treatment. In a non-randomized prospective controlled study, we compared two discharge protocols in consecutive patients admitted for acute severe exacerbations of bronchial asthma. Patients in group A were discharged after remission of signs and symptoms and those in group B after improvement but before complete remission of signs and symptoms. Peak expiratory flow rates (PEFR) were monitored but were not used as discharge criteria for either group. Patients with complicating disease and who were likely to be non-compliant were excluded. The length of hospital stay (LOS) and best PEFR at discharge were significantly lower in group B (87 admissions) than group A (80 admissions). The mean (+/-SD) LOS was 1.8(+/- 1) days vs. 3.5(+/- 1.4) days and best PEFR was 58(+/- 17)% predicted versus 71(+/- 15)% predicted respectively (P < 0.001 for both variables). No patient in either group relapsed within 4 weeks of discharge from hospital. We concluded that the release of asthmatics who respond promptly to intensive treatment and are compliant with medication despite incomplete resolution of symptoms, signs and PEFR at the time of discharge from hospital may not be associated with increased risk of early relapse.

Severity and associated risk factors in adult asthma patients in Turkey

BACKGROUND

The prevalence of asthma of varying severity and associated risk factors are unknown in Turkey.

OBJECTIVE

The study investigated the distribution of asthma severity, the factors having roles in asthma severity, and the relationship between serum eosinophil cationic protein (ECP) levels and disease severity.

METHODS

Three hundred patients with asthma (73 male, 227 female) were enrolled in the study. The patients were surveyed for their smoking habits, educational levels, household incomes, asthma duration, occupations, and accompanying diseases. ECP levels were also determined in certain patients representing different disease severities (n: 76) and in a control group (n: 9).

RESULTS

Patients were classified as mild intermittent (n: 14, 5%), mild persistent (n: 220, 73%), moderate (n: 44, 15%), and severe asthma (n: 22, 7%). Cigarette consumption and educational status were similar in all groups. A longer duration of disease and an older population predominated in patients with moderate and severe asthma. Analgesic sensitivity was seen in 7%, 10%, 6%, and 31% of mild intermittent, mild persistent, moderate and severe asthma patients, respectively, with the highest ratio in severe asthma (P < .05). Nasal polyps were significantly higher in severe asthmatics. Atopy was diagnosed in 85%, 57%, 56% and 10% of mild intermittent, mild persistent, moderate and severe asthma patients, respectively. ECP levels were significantly higher in moderate and severe asthma patients.

CONCLUSIONS

Mild asthma was the most common clinical presentation and was associated with atopy. The factors associated with severe asthma included prolonged asthma duration, advanced age, nonatopy, analgesic intolerance and nasal polyps. ECP levels also reflected disease severity.

Categorizing asthma severity

The National Asthma Education and Prevention Program (NAEPP) Expert Panel II recommended a stepped care pharmacotherapy approach to asthma treatment based on an objective assessment of asthma severity using daytime symptoms, nocturnal symptoms, and physiologic lung function. The worst grade of the individual variables determines overall asthma severity. With this approach, patterns of asthma severity categorization might vary among individual variables; one variable might have a predominant effect on overall categorization. During the run-in, pretreatment phase of five controlled clinical trials, data from 744 inhaled steroid nonusers and 685 inhaled steroid users on asthma control were collected and asthma severity categorized. In inhaled steroid nonusers nocturnal symptoms classified the majority of patients as severe, persistent, but wheeze classified 27.3% of patients as mild, intermittent and 25.7% as mild, persistent. If the worst grade from the four asthma symptoms was used for severity grading, most patients were categorized as severe, persistent. beta-Agonist use and FEV(1) classified most as moderate, persistent. There was poor correlation between variables in severity categorization. Severity grading for European patients was similar to that for U.S. patients. Applying the Expert Panel II recommended method for asthma severity categorization to a large data set illustrates that a single variable, nocturnal symptoms, determined to a large extent overall categorization. Development of a validated method for asthma severity categorization is essential for using a stepped care approach to asthma pharmacotherapy.